Photopolymerization of acrylamide

July 7, 2005 10:15 AM

Attention molecular biology nerds: have you any experience with photoinitiation of acrylamide gel polymerization?

Our lab has an MJ BaseStation, which we purchased along with a ton of pre-packaged acrylamide, the kind that comes in an "instant ice-pack" style pouch. Said acrylamide includes a photoinitiator that lets us cast and polymerize a sequencing gel in less than 10 minutes. Very convenient, no need for APS/TEMED and long pre-runs on the sequencing machine.

Problem is, the pre-packaged stuff is getting old (4 years past the expiry date), and we're getting increased background noise compared to a fresh acrylamide that we polymerize the old-fashioned way. So, I'm looking to combine the best of both worlds -- fresh acrylamide that can be polymerized with a photoinitiator. Of course, we can buy a pre-made photoinitiator solution, but it's a bit pricey, and they won't tell us what's in it.

I've tried riboflavin, but it didn't work. This patent claims that 1-hydroxy-cyclohexyl-phenyl-ketone works well as a photoinitiator. The only problem I can see is that its max UV absorbance is at 250nm or so, while our UV box has its peak output at 312nm. For that reason, I thought 2-Methyl-4'-(methylthio)-2-morpholinopropiophenone might be a better choice.

So, to make a long story short, has anyone used either of these for photopolymerization? Or have you used anything else that works reliably?

posted by greatgefilte to technology (2 comments total)

I've used something from CIBA called Irgacure 2959. It's water soluble up to about 1% w/v. It has a pretty broad UV absorbance, peaking at like 280. You should be able to initiate it at 312, especially at higher concentrations.

I requested a free sample, and they sent me a whole bunch....
posted by mr_roboto at 12:33 PM on July 7, 2005

Thanks! Any idea at what concentration you used it?
posted by greatgefilte at 9:18 PM on July 7, 2005